Key Information: Statewide mosquito trapping and test results are listed, as well as animal and human cases by county. Mosquito pooling refers to the collection and combining of mosquitoes for virus testing. The Rhode Island Department of Environmental Management (DEM) traps mosquitoes at various locations throughout Rhode Island and later separates the mosquitoes of each trap into 'pools' according to species. The State Health Laboratory tests each pool for the presence of virus.